The commercial roofing market offers a variety of coating kinds. Facility managers should review the manufacturer’s material data sheets to identify which product is appropriate for their particular project because the material compositions, uses, and application techniques vary. On some roof surfaces, not all coatings are suitable or compatible. Additionally, all pre-application preparation should be finished under the guidelines set forth by the producer of the roof coating. All of these products have a set shelf life, much like all liquids and adhesives used in the roofing business, thus proper on-site material storage is crucial.
Silicone Coatings
| GacoRoof GR1600-1 White Silicone Roof Coating – Gallon | AMES RESEARCH LABORATORIES MSS1 Maximum Stretch Roof Coating, 1 Gallon, White |
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Silicone roof coatings are the finest choice for UV protection and water resistance. Unlike other coatings, they don’t become brittle or hard, but they do degrade much more slowly. More than 90% of modern silicone formulations are usually made up of solids. This shows that less amount of material is needed to achieve the appropriate dry film thickness. To create silicone coatings, a silicone base is mixed with solvents and a catalyst. A variety of roofing materials, including metal, modified bitumen, single-ply EPDM, built-up roofs, and spray polyurethane foam, can be coated with silicone. It comes in tan, grey, or white. Depending on the substrate, the majority of silicone roofing systems require numerous coats at a rate of 1.5 gallons per 100 square feet.
Silicones are fairly good at drawing dirt. This indicates that if the system is not regularly cleaned, the reflectivity will steadily decrease over time. When there is moisture present, they become incredibly slippery. Another innate flaw is resistance to tearing. We strongly advise including roofing granules in the system if there will be foot traffic on the roof.
Acrylic coatings
Acrylic coatings were initially developed to provide ultraviolet protection for sprayed-on urethane foam applications. Currently, these coatings are applied to a variety of roof membrane surfaces, including single-ply membranes and metal roofing systems. Materials based on acrylic have the inherent flexibility required to overcome the dimensional instability of the majority of roof membrane surfaces, and they also provide effective radiation and hail damage defense. According to some research, suitably formulated acrylic coatings can reduce surface temperature by as much as 20 degrees F when exposed to direct sunlight at 85 degrees F.
Acrylic makes up the entirety of acrylic coatings, which can be put in one or more coats. Most manufacturers base their warranties on rates of coverage; extended warranties demand greater coverage. Acrylic coatings should not be used if it is likely to rain or snow within a particular period following application or if it will be below freezing. The weather has a big impact on how long these things take to mend; cold or humid weather will cause the cure to take longer. For healing, a warm, dry environment with little humidity is optimal.
Nowadays, several acrylic coating producers provide instant-set products. This shortens the acrylic coating’s cure period to a few minutes, eliminating the chance of coating run-off if it rains right after application.
Asphalt Emulsion
Asphalt emulsion is another product that is frequently used for roof rehabilitation. This product is made up of clay acting as a binding agent and asphalt particles dispersed in water. Asphalt emulsion, which is often black or brown, comprises both organic and inorganic asphalt emulsion is affordable and simple to use. On modified bitumen and built-up roof surfaces, it is generally used to level “alligatoring” and other imperfections that frequently happen. Asphalt emulsion is often utilized to create a monolithic foundation membrane for other elastomeric roof coating methods that offer superior reflectivity and UV stability, even though it can be put as an independent roofing material.
Depending on the substrate, an asphalt emulsion application typically requires 3 to 4 gallons per 100 square feet. To get the best results, you might need to make several passes. Substances as well as additional fillers increase strength and longevity.
Butyl Rubber Coatings
Butyl coatings are a type of polymer with a solvent basis that are renowned for having remarkable elongation and tensile strength. They work well for roof maintenance and repair since they are highly reflective and quick drying. Butyl rubber coatings are most frequently employed as a vapor-retardant barrier over spray polyurethane foam systems in cold storage/freezer applications because of their low permeability.Several commercial roof surfaces, including metal, modified bitumen, single-ply, built-up roofs, and spray polyurethane foam, are appropriate for butyl coating systems.
They can be sprayed or applied in rolls at a rate of roughly 2 gallons per 100 square feet, and are commonly white, grey, or tan. Butyl coating’s low solids concentration is its main drawback. This makes it less cost-effective than other coating types since it requires more liquid material to reach a given dry mil thickness. They can also be difficult to deal with and have unstable colors.
Polyurethane coatings
The original purpose of polyurethane coatings was to cover foam roofs that had been sprayed in place. Currently, they are put as coatings over a variety of already-installed roof membranes. Polyurethane coatings give the best rates of any coating for impact resistance and foot traffic. Both aromatic and aliphatic polyurethane roof coatings are available. Usually, this kind of ingredient is blended with the base coat and topcoat. Although the base coat’s composition is strong, it has only average UV resistance. The aliphatic coating is used as a top surface because it is UV stable, keeps itself clean, and preserves color longer than other coatings.
Situations to Consider
The location and construction of your building will determine the optimum roof coating. You must also take preferences into account, such as simplicity of maintenance, longevity, energy savings, etc.
However, the following list of circumstances is a broad summary of what to take into account when selecting a roof coating:
- Extreme heat: If you reside in an area that experiences extreme heat, you should use a highly reflective coating material. Typically, you desire a reflectivity rating of 85% or above. Typically, this also refers to silicone and acrylic roof coatings. The ability of a substance to emit heat after being absorbed is measured by an emissivity, which may also be necessary for extremely hot environments.
- High Foot Activity: A roof coating with a high solid-by-volume composition is generally necessary if there is a lot of foot traffic on your roof. Once the application has dried, a roof coating material’s greater solids by volume will be more solid.
- : In cases of heavy rain, you should use a roof coating material with a low permeability rating. You will have the best chance of preventing leaks and water damage if you do this. Coatings made of butyl are usually appropriate for these circumstances.
